Most people have a number of brownish spots on their skin -- freckles, birthmarks, moles. Almost all such spots are normal, but some may be skin cancer. The key warning signs of melanoma are shown below. Be alert to irregularities in shape, edges, color and size. If you detect any of these warning signs, see a physician promptly. The ABCDs of melanoma are Asymmetry, Border irregularity, Color variability and Diameter larger than a pencil eraser:

Asymmetry
Most early melanomas are asymmetrical: A line through the middle would not create matching halves. Common moles are round and symmetrical.

Border
The borders of early melanomas are often uneven and may have scalloped or notched edges. Common moles have smoother, more even borders.

Color
Common moles usually are a single shade of brown. Varied shades of brown, tan or black are often the first sign of melanoma. As melanomas progress, the colors red, white and blue may appear.

Diameter
Early melanomas tend to grow larger than common moles -- generally to at least the size of a pencil eraser (about 6mm, or 1/4 inch, in diameter).

How Does a Mole Change?

In addition to checking out the ABCDs, you should watch for change.

Size
The mole suddenly or continuously gets larger.

Color
A wide variety of colors or color combinations appear. Color might spread from the edge into the surrounding tissue.

Elevation
A mole that was flat or slightly elevated increases in height rapidly.

Surrounding skin
The skin around a mole becomes red or develops colored blemishes or swellings.

Surface
A smooth mole develops scaliness, erosion or oozing. Crusting, ulceration or bleeding are signs of more advanced disease.

Sensation
Itching is the most common early symptom, and there may also be feelings of tenderness or pain. Nonetheless, remember that skin cancers are usually painless.

If any of these changes occur, they should be checked by a professional. It is particularly important for you to select a physician who specializes in skin cancer and is trained to recognize a melanoma at its earliest stage. You would first see a dermatologist, who might refer you to a dermatologic surgeon or oncologist (cancer specialist). Make an appointment without delay.

Source:
The Skin Cancer Foundation